Pressurized fluid cylinders are used in various settings. For example, a self-contained breathing apparatus (SCBA) typically includes an air cylinder that is used to provide safe, clean air to an individual for breathing. An SCBA is configured to be worn by individuals, such as rescue workers, firefighters, and others, to provide breathable air in a hazardous or otherwise unsafe atmosphere. When configured for use underwater, an SCBA is typically referred to as a self-contained underwater breathing apparatus (SCUBA).
An SCBA typically includes a high-pressure tank (for example, 4,500 psi) that connects to a pressure regulator, which in turn connects an inhalation connection, such as a mouthpiece, mouth mask, or face mask. At least one of the tank, regulator, and inhalation connection may be secured to a carrying frame that allows an individual to carry the SCBA on his/her back, for example.
After use, a fluid tank or cylinder needs to be re-filled for future use. One system and method for filling a fluid container includes a plurality of storage cylinders. For example, four storage cylinders may be connected together. Fluid within the storage cylinders may be sequentially drawn from the storage cylinders to the fluid container. A known method of filling a fluid tank includes manually operating the storage cylinders. However, human error may result in the fluid tank being under-filled, for example.
Accordingly, automatic systems and methods have been developed to fill a fluid tank. A sequence valve may be used to determine fluid pressure within a fluid cylinder to be filled, and fluid pressure within the storage cylinders, and then fill the fluid cylinder from the storage cylinders in sequence.
A known automatic system provides an auto cascade system that is used to fill a fluid cylinder. A typical auto cascade system includes multiple pipe thread fittings strung together with tubing and framed in a sheet metal enclosure. The process of assembling a typical auto cascade system is generally labor-intensive. Further, a typical auto cascade system is prone to leakage, due to the numerous fittings and connections. Also, a typical auto cascade system is difficult to service. Moreover, a typical auto cascade system is bulky and is usually mounted externally to a pneumatic control system and joined to it via multiple high pressure hoses.
A known system and method includes a series of cartridge type sequence valves inserted into a manifold block arranged in a linear fashion. However, this manifold system utilizes external plumbing between the cartridge valves, and external plumbing to other parts of the pneumatic control system. Further, the cartridge valves typically include large diameter radial seal O-rings that are prone to leakage under high pressure.